JPS6213578A - Additive material for surface alloying and cladding by laser light - Google Patents

Abstract

PURPOSE:To form a laser alloyed layer and cladding layer having no defects by using an additive material contg. a hard compd. or the constituting element thereof and a metal or alloy having the m.p. lower than the m.p. of the hard compd. or the constituting element thereof. CONSTITUTION:The additive material for surface alloying and cladding by laser light is obtd. by incorporating the hard compd. having high hardness such as compd. of a metal such as V, Ti or Nb and C, N, O, B, etc., or intermetallic compd. of Fe, Co and Ni and Ti, Zr, etc., or the element constituting the same and the metal such as Fe, Ni or Co having the m.p. lower than the m.p. of the above-mentioned hard compd. or the alloy thereof and the constituting element thereof into said material. The above-mentioned additive material can be constituted of a powder mixture composed of the powder particles of the hard compd. and the powder particles of the metal or alloy having the low m.p. or the powder mixture of the respective powder particles of the constituting elements thereof and is preferably applied in the form of a sintered powder molding.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to additive materials used for laser alloying and cladding of base metal materials using laser light.
More specifically, the present invention relates to additive materials used in laser alloying and clap-doping, which are performed to improve the wear resistance, heat resistance, etc. of base metal materials.

Conventional technology Laser surface alloying is a processing method in which a thin molten layer is created on the base metal by laser heating, and the necessary alloying elements are added to this and diffused almost instantaneously to form an alloy layer on the base metal surface. be. The method of adding such alloying elements is (a)
(b) Method of heating and melting the surface of the base material and adding the additive material to the molten pool. In the case of (a), the additive material in the form of powder, thin plate wire, or foil is also (
In case b), wire or powdered additive materials are usually used.

On the other hand, laser cladding is a process very similar to laser alloying, in which the amount of melted base material is reduced by adjusting the amount of additive material and laser irradiation conditions, and the additive material is placed on top of the base metal material. This is a technology that forms (coatings) the entire surface layer with a composition close to that of the ingredients.

Both surface alloying and crapping use low-cost base materials, while improving corrosion resistance and corrosion resistance in only the minimum necessary areas.
Since it is possible to form a surface layer with excellent wear resistance, heat resistance, etc., research on these matters has been very active in recent years.

In such alloying and cladding using laser light, additive materials are used that can impart desired properties to the base metal.

When mainly imparting corrosion resistance, Cr5Si1A12s
Metal elements that form a strong oxide film, such as metal elements, are added, but since they all have low melting points and a small amount of addition produces a large effect, there is no particular problem with their addition.

On the other hand, when providing wear resistance and heat resistance, TiC1VC and NbC, which usually have high hardness.

Metal carbide such as WCSMoC, TaC; TiN, Ao
,N.

Metal nitrides such as NbN and VN; A(!tO+, TiO
2. Metal oxides such as Cr t O3 and Z r O2 are added.

By adding metal compounds with such high hardness, (
1) Dispersion hardening that occurs due to fine crystallization of these compounds during cooling, (2) Solid solution hardening that occurs because some of these compounds do not crystallize and are forcibly dissolved in the matrix. 3) By further aging after laser alloying, precipitation hardening occurs by re-precipitating these compounds dissolved in the matrix, and these hardening mechanisms aim to increase hardness and improve wear resistance. However, these metal compounds have very high melting points, and the addition of large amounts can cause various problems as described below, so at present, only small amounts of these compounds can be added to slightly improve wear resistance and heat resistance. Only.

The problem to be solved by the present invention is that when a large amount of a high melting point compound is added in the alloying treatment or tarading treatment of the base material using laser light, the following problems occur.

(1) The compound is very difficult to melt, and if a large amount is added, the unmelted compound remains in the alloyed layer. Since this unmelted compound usually exists in an aggregated state, it easily falls off and becomes a cause of defects such as bores and cracks.

(2) Even if it melts, it has a high viscosity, so it does not mix uniformly with the liquid phase of the base material, resulting in a partially uneven structure. Moreover, the bubbles do not completely escape to the surface and remain as defects in the alloyed layer.

(3) When the specific gravity of the additive material and the base material are different (AQtos,
The above-mentioned unevenness is more pronounced in SiC, Fe, Ni, etc.).

Means for Solving the Problems The present invention provides (a) a hard compound having high hardness or an element constituting the hard compound; and (b) a metal or alloy having a lower melting point than the hard compound or containing an element constituting the alloy. The present invention provides an additive material for surface alloying and clapdding by laser light, which is characterized by:

Complete melting of the added hard metal compound can be achieved by heating the compound above its melting point or by treating individual compound particles with a solution of a metal or alloy that has a lower melting point and forms a liquid phase with the compound. The reaction with the covering solution must be utilized.

When the amount added is small, it is relatively easy to heat the metal compound to above the melting point even if it is added alone, and even if the metal compound is not heated above the melting point, the base material liquid can be heated with little agglomeration of the powder. Since it is added to the phase, it quickly melts by reaction with the liquid phase.

However, if the amount added is large, the uniform particles of the metal compound will aggregate and the contact area with the base material liquid phase will become small, making melting very difficult.

The present invention has discovered that such problems can be solved by allowing a metal or alloy phase having a lower melting point than the metal compound to exist in the additive material together with the metal compound.

That is, when the additive material of the present invention is heated, the low melting point metal or alloy phase first melts, and the individual hard metal compound particles are covered with the liquid phase of the metal or alloy. A liquid phase consisting of a hard metal compound component and a metal or alloy liquid phase is formed almost instantaneously. Therefore, it is extremely difficult for unmelted metal compounds to remain, and even if melt remains, these compounds are extremely difficult to fall off because the metal or alloy phase exists between the hard metal compound particles. Furthermore, since the viscosity of the obtained liquid phase is reduced, the base material liquid phase and the metal compound are mixed uniformly, and no defects such as bubbles remain.

Furthermore, cladding by adding a hard metal compound alone in the absence of the base metal was previously impossible, but since the additive material of the present invention is easily melted without being mixed with the base metal in advance, cladding is also possible. .

The hard metal compound and metal or alloy used to form the additive material of the present invention will be explained in detail below.

(a) Hard compound V, Ti1NbSHf, Zr, Ta, Mo5W, Cr,
Most metals such as Fe, 5isCo, A12, and C
Compounds with light elements such as , N, OlB: F es C
as N r, T i, Z r.

Hf, V, Nb, Ta, Cr, Mo5W, A(2SRe
, Si, Mn, etc., and intermetallic compounds of Mo and Si: Compounds of light elements such as BN have extremely high hardness and can be used as hard compounds in the present invention. One or more of these compounds may be used in combination in the additive material.

(b) Metal or alloy Fe, Ni, Go, A12. Ti, CrSMn, Zr,
A metal having a lower melting point than the hard compound, such as simple Cu, can be used, but it is desirable that the specific gravity of the additive material be close to that of the base material.

In addition, Mo
5W, C, N, B and other elements may be added.

The form of the additive material of the present invention consisting of (a) a hard compound and (b) a metal or alloy phase with a lower melting point than the hard compound will be explained with reference to schematic diagrams (Figures 1 to 3). do. That is, the additive material of the present invention comprises (a) mixed particles produced by mixing powder particles (1) of a hard compound and powder particles (2) made of a metal or alloy, as shown in FIG. 1a. (b) As shown in FIG. 2, the powder particles (3) may include a single particle composed of a hard compound and a metal or alloy component.

To create the latter (b) additive containing single particles, either atomize a molten metal consisting of the desired hard compound component and a metal or alloy component (Figure 2b, Figure 2C);
Alternatively, there is a method of coating the surface of a hard compound powder with a metal or an alloy component by plating, vapor deposition, ion sputtering, etc. (FIG. 2a), or conversely, a method of coating a hard compound on the surface of a metal alloy powder. The additive material (b) is superior in terms of laser surface alloying, ease of melting the compound during cod pudding, alloying, and quality of the cluttering part, but special equipment is required for its production. Since the unit cost of additive materials is high, they are used depending on the purpose of alloying and cladding.

In addition, in the case of the additive (b), the hard compound phase and the metal or alloy phase do not necessarily need to exist separately in each powder particle, but each element constituting the hard compound and the metal or alloy phase do not necessarily have to exist separately. The elements constituting each may be wholly or partially dissolved in solid solution with each other (Fig. 2 or C).

In addition, regarding the additive material consisting of mixed particles, it is not necessary to use the powder itself consisting of a particularly expensive hard compound as shown in (a), and (c) each element constituting the hard compound as shown in Figure 1. constitute separate powder particles, for example, in the case of VC carbide, V powder (1) and C powder (1') may be further mixed with metal or alloy powder (2). A mixture of each of the additive materials (c) may also be used.

Furthermore, as other forms of the additive material of the present invention, (d) those obtained by sintering the powders of the forms (a) to (c) above into a thin plate (Fig. 3), wire, or other appropriate shape are particularly preferred. . Such baked crystals have a better yield during alloying and tara pudding than powdered additive materials, and it is easy to maintain a constant supply amount.

Effects of the Invention Laser surface alloying and cladding using the additive material of the present invention produces a surface layer with very high hardness without causing defects in the alloy layer or cladding layer, so it is suitable for various machines having sliding parts. It becomes possible to significantly improve the wear resistance and heat resistance of parts and tools such as cutting tools and cold and hot forming tools.

EXAMPLES The present invention will be explained in more detail below with reference to Examples. In the examples, % means weight %.

Example 1 Various test additive materials were manufactured by the following method using the components and blending amounts shown in Table 1 below.

Conventional products: Commercially available VCSTiC and AltO *Purity:
>99.0% Particle size: 1 to 6 μm Manufacturing method (a) Mixing powder particles of two hard compounds and powder particles made of metal or alloy to produce mixed powder Manufacturing method (Row a): Stirring hard compound powder A manufacturing method in which the powder surface is coated with an alloy by vacuum deposition (Row b, c) and a manufacturing method in which a molten metal consisting of a hard compound component and an alloy component is atomized (c): tEl! Production method (d) of mixing separate powder particles of each element forming a compound and metal powder: The mixed powder produced in the production method (a) is pressure-molded using a hot static press, and then, Various test additive materials obtained by slicing into thin plates of 0.5 mm thickness were subjected to laser alloying (cratching) under the following conditions within the limit that no defects would occur. The hardness of the obtained alloyed layer (Taratuding layer),
That is, the maximum hardness that can be alloyed is shown in Table 2 below.

Laser irradiation conditions: Output = 1~5kW Workpiece movement speed: 1m/min Spot diameter: 5i1R Base material: 515C1 pure titanium, pure aluminum Generally,
The surface hardness tends to increase as the amount of hard compound added increases, but when only a hard compound is added (additives 1 to 3), a relatively small amount of addition can cause problems such as bores, texture unevenness, and agglomeration of unmelted compounds. Defects occur, and the hardness obtained without defects is less than <Hv900, as shown in Table 2. On the other hand, when Additives 4 to 38 of the present invention are used, high hardness of Hv900 or higher is achieved without any defects.

Table 1 Table 1 (continued) Table 1 (continued) Table 2 Maximum Vickers hardness (HV; load 2009) of alloyed (clapping) layer that can be formed without defects Table 2 (
(Continued) Table 2 (Continued)

[Brief explanation of the drawing]

1 to 3 are schematic diagrams showing the form of the additive material of the present invention. Patent applicant: Kobe Steel Oriyoshi Co., Ltd. Patent attorney: 2 people (including the above) Figure 1: 0
Figure 1 Figure 2 Figure 0 Figure 2 b Figure 2 C Figure 3

Claims (5)

[Claims] (1) A laser beam characterized by containing (a) a hard compound having high hardness or an element constituting the hard compound, and (b) a metal or alloy having a lower melting point than the hard compound, or a constituent element of the alloy. Additive materials for surface alloying and cladding by. (2) The above-mentioned (1) contains a mixed powder in which a hard compound is the main component to form the first powder particles, and a low melting point metal or alloy is the main component to form the second powder particles. Added materials in section. (3) The additive material according to item (1) above, wherein the element constituting the hard compound and the low melting point metal or alloy constituent element contain a single particle forming each powder particle. (4) The additive material according to item (1) above, which contains a mixed powder in which each element constituting the hard compound forms separate powder particles, and a low melting point metal or alloy further forms other powder particles. (5) The additive material according to item (1) above, which is in the form of a powdered sintered product.